Memphis Depay, Matteo Darmian, Bastian Schweinsteiger, Morgan Schneiderlin and Sergio Romero – Manchester United have bought well in this summer transfer window, and the first of many, many steps which will show if these are indeed the right signings will be taken with the opening match of the Premier League season – against Tottenham at Old Trafford on Saturday.

Even if Manchester United picked up three victories in their four preseason games in the International Champions Cup 2015, they weren't entirely convincing, with Louis Van Gaal again showing he might not yet know what his best XI is.

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Having signed the four new players relatively early in the transfer window, Van Gaal has had enough time to inculcate his "philosophy" into them, and the first game will show a glimmer of just how far this Manchester United team can go this season.

Manchester United made an awful start to their Premier League campaign last season, going down to Swansea City 2-1 at Old Trafford, and the last thing Van Gaal will want is a repeat of that performance and result.

A quick start is essential if Manchester United are to challenge for the Premier League title this season, because, as Chelsea showed last campaign, if you take a big lead early, the chances of keeping that advantage right until the end of the season are pretty good.

Van Gaal has gone with a 4-2-3-1 formation in preseason, despite promising a 4-3-3, with Depay, puzzlingly playing as the No.10, behind main striker Wayne Rooney.

Depay thrives when coming in from the wide positions, and with a more astute No.10 in Juan Mata in the lineup, one does wonder what Van Gaal's thinking is behind it.

While there are issues to be ironed out up front – not so much in midfield, with the Dutchman having more than enough options – the defence remains a problem, with Chris Smalling expected to lineup alongside Daley Blind in the centre of the back-four for the first match against Tottenham.

If the duo can spark a partnership, Van Gaal will breathe a huge sigh of relief, because otherwise it could prove to be another topsy-turvy season for that defence, especially if David De Gea leaves for Real Madrid.

Tottenham also come into this opening Premier League match with plenty of questions, with the biggest one of them being Harry Kane.

Reports earlier this week suggested Manchester United had made a massive bid for Kane, with the striker, surprisingly, sitting out of Spurs' match against AC Milan in the Audi Cup 2015 third-place playoff.

It goes without saying that Mauricio Pochettino relies a little too heavily on Kane for goals, and having not signed a new striker so far this season, the manager will not want to lose the England forward.

Kane will be a marked man this season after his breakout campaign last year, and how he performs in front of goal will prove to be a big factor in this opening marquee matchup.

With the Manchester United defence looking a little iffy still, Kane will fancy his chances of opening the new Premier League campaign with a few goals.

Another key player for Tottenham this season will be the new signing Toby Alderweireld, who is finally expected to shore up the team's defence alongside Belgium compatriot Jan Vertonghen.

"I've played a lot of big games so I know what to expect," Alderweireld, who impressed so much at Southampton last season, told the club's official website. "The first game of the season is always a strange one. Everybody is very excited and we're looking forward to it. It's a big challenge.

"We have the opportunity to take a good first step. We are confident we can get a good result but we know it will be difficult.

"They have brought in a lot of good players but we've had a good pre-season and trained hard so physically we are 100% and we want to get a good result to start the season.

"We have confidence in ourselves to play football. It's always difficult to play at Old Trafford but we have to believe in ourselves and how we want to play. If we do that, we can get a good result."

Expected lineups: Manchester United: De Gea; Darmian, Smalling, Blind, Shaw; Schneiderlin, Carrick; Mata, Depay, Young; Rooney.

Tottenham: Lloris (if he is fit); Walker, Alderweireld, Vertonghen, Rose; Mason, Bentaleb; Eriksen, Dembele, Chadli; Kane.

Manchester United vs Tottenham Schedule: Saturday, 8 August (12.45 pm BST, 5.15 pm IST, 7.45 am ET) at Old Trafford.

Live TV coverage in India, UK and US will be on Star Sports 4, BT Sport 1 and NBC Sports respectively.